The Mirror Middleman wears his hair long with a goatee, and wears leather chaps and vest. He wears an eyepatch over his right eye. He is foul-mouthed, greedy, and supremely unconcerned with the plight of others. He resides at the mirror version of Middleman Headquarters, but seems to do nothing besides working on his motorcycle, the Middlehog, unless he is paid.
Wendy Watson, after being sucked through a quantum singularity into the mirror universe, goes to him for help. When he refuses unless she pays him, she gives him her bracelet, and he assists her in capturing Ivan Avi. After a brief interrogation, in which Wendy and the Middleman are at odds over how violently or not to question Avi, Ivan receives a psychic message from his good twin, revealing how Wendy can return home. When he grabs Wendy and her gun, intending to hold her ransom, the Middleman simply shoot Ivan to death with his Middle-Gun.
After refusing to accompany Wendy to recover the phased polaron cannon from Fatboy Industries, the Middleman has a changed of heart and rescues her, sacrificing the Middlehog in the process. After Wendy returns to the regular universe, the Middleman decides to stay and fight Fatboy. He shaves his goatee and takes the normal Middleman's uniform, recruiting Mirror Lacey as his sidekick.
At the onset, the Middleman has a bad record. He lost his eye to Sensei Ping, who plucked it out; in retaliation, the Middleman betrayed Sensei Ping to the Mexican Luchadores, who murdered Sensei Ping at the Dread Pyramid of Itzilichlitlichlitzl. The Middleman further forsook duty when his original sidekick, Tyler, was killed. However, after saving Wendy, his true goodness shone through; when she returned to her apartment in the normal universe, Wendy discovered that the mirror Middleman had slipped her back the bracelet.
Mirror Wendy was originally Lacey's roommate, as in the normal universe, but she betrayed Lacey in their first year of art school, and had Lacey arrested and sent to Fatboy Darning Camp to make stormtrooper socks and underwear. She subsequently became the right hand to Manservant Neville, aiding him in conquering the United States. When Manservant Neville planned to return power to the people, however, Wendy had him cryogenically frozen and covertly assumed control of Fatboy. During the rise of Fatboy, she also murdered Tyler Ford.
Wendy was driven by the loss of control that her father's mysterious and as-yet unexplained disappearance made her feel, and resolved never to lose control again. As such, she tightened Fatboy's control far beyond what Manservant Neville envisioned, until it became a totalitarian regime. Mirror Wendy was totally sociopathic, murdering Joe Ninety in cold blood and condemning both Lacey and normal Wendy to death by firing squad. She was foiled only at the last second, by the mirror Middleman.
Mirror Lacey was betrayed by mirror Wendy, and spent two years making stormtrooper socks and underwear. Subsequently, she returned to her loft, which is an exotic dance bar. Unlike normal Lacey, mirror Lacey is not a vegan or concerned with animal rights; indeed, she has a popular recipe for rabbit stew.
Lacey teams up with normal Wendy and Joe Ninety to recover the phased polaron cannon from Fatboy. In doing so, she discovers the two Wendys before they are rescued by the Middleman. After normal Wendy returns to the normal universe, Lacey becomes the new sidekick to the reforming Middleman.
The mirror universe version of Ida is not stuck on "domineering schoolmarm version 2.0", but instead has a fit, athletic young woman's body. Given that the Middleman has abandoned his duty of protecting the world, she spends her days tanning in a tanning bed, rejoicing in the fact that she can not get cancer. However, after initial sarcastic hostility, she becomes concerned for Wendy and chides the Middleman for failing to help her.
Once the Middleman reforms, he switches Ida back to her schoolmarm appearance, apparently to her pleasure.
In the mirror universe, Noser is the bodyguard and bouncer at Lacey's loft. His banter with Wendy from "The Pilot Episode Sanction" ("Who's the man?"...) is used as a password to enter Lacey's. Anyone who does not answer correctly, Noser kills with a shotgun. He also attacks Fatboy stormtroopers on sight.
In the mirror universe, given that mirror Wendy threw in with Fatboy, Tyler was hired as the Middleman's sidekick instead. However, on a mission, the two were separated, and Tyler was killed by mirror Wendy.
Mirror Joe Ninety is a playboy lawyer for Fatboy. When normal Wendy and Lacey present him with photographic evidence of his womanizing, he agrees to get them into Fatboy Headquarters. He triggers the silent alarm secretly to warn his boss, the mirror Wendy, but she repays him for his earlier betrayal by killing him with a gunshot to the chest.
In the mirror universe, Pip is a priest, who makes it his business to rescue and protect as many people as he can from Fatboy. It is being rescued by Pip and their ensuing conversation that convinces Wendy she has been sucked into the evil universe.
Formerly the leader of Fatboy Industries, Manservant Neville led a war against the United States, culminating in the Battle of the District of Columbia. After winning the battle, Fatboy became the ruling government of the United States. However, after a time, Manservant Neville grew disillusioned with what he had done, and wanted to restore control to the people (and go green). Mirror Wendy prevented this by locking Manservant Neville in a cryobed and assuming control of Fatboy.
- Every male character in the evil universe (even those who aren't evil, like Tyler) has a mustache and goatee. The Middleman shaves his at the end of the episode, when he reforms.
- Manservant Neville's conquest of the United States, and subsequent desire to restore power to the people, is a foreshadowing of "The Doomsday Armageddon Apocalypse". In the real universe, Manservant Neville takes power with theoretically good reasons, but becomes so corrupted that he is beyond redemption.